Drawer slides are necessary components in the manufacture of quality cabinets and furniture of various kinds. Some of the more demanding applications are found in the office furniture industry where the drawer slide function must satisfy the customers of the office furniture manufacturer.
The most fundamental purpose of the drawer slide is to provide smooth and effortless movement of a drawer to which it is attached, from a closed position to an open position. Sometimes this is accomplished by two channel members that slide in relation to each other, either by means of a roller or by means of ball bearing support. With respect to the present invention, it is the stop function of the drawer slide, that is the means by which the drawer slide is made to stop at the end of its desired travel, and the ability to override the stop mechanism for drawer removable, that is the primary subject herein.
Stop lever assemblies are known that allow for competent stopping of the drawer at the end of its travel while providing convenient means for removal of the drawer once the stop is overcome. One such stop lever assembly utilizes a lever that is interior to the channel member that is affixed to the drawer to disengage a drawer from the slide assemblies. Normally, a central raised portion of the lever is able to contact a corresponding stop found on the opposing channel member. Thus, as the drawer is opened, it travels unimpeded until the stop lever engages the stop, thereafter preventing any further forward travel. In order to remove the drawer, it is necessary for the user to actuate a tab that extends from the stop lever into a position where it clears the stop. After accomplishing this, the drawer with attached channels is free to be removed from the cabinet. One lever or one side is raised and the second lever of the second side is lowered A subsequent improvement enabled the levers on both sides to be raised. However, these are ergonomically difficult to operate and they tend to stick and jam.
Another type of stop lever utilizes an action that works in the same direction of travel as the drawer and the slide. The tab extends forward from the area of the stop and has a loop in the end for the user to engage. Once the loop is pulled forward for the desired distance, the stop is overcome and the drawer and channel can be removed from the cabinet. Other stop levers are known in the drawer slide industry, but they typically share much of the above-described approaches.
The space allowed for stop lever mechanisms within the inner channel is extremely limited, since the entire rail assembly is only a short one-half inch in width. Thus, the usage of a mechanism is usually severely constrained by the design of the channel. At least in the vertical directions, the throw that a given tab or lever may have is determined by the clearance allowed within the inner channel. The lever that utilizes the line of travel action has a longer throw but requires the user to affirmatively engage the loop and pull it sufficiently forward. This action is clumsy and awkward and not as easy for everyone to accomplish as the vertical action. It would be convenient to be able to simply push a stop release lever inwardly-laterally towards the drawer walls when releasing the slide But the tiny clearance between the rails has, as far as is known, prevented an effective release of this type.
Another difficulty with present mechanisms involves the movable stop lever block face that is in abuttable alignment with an opposing fixed stop block face. These block faces are substantially perpendicular to the line of travel of the slide mechanism. This construction is known to fail its purpose as an end stop at times, when the user opens the drawer faster than normal. What appears to happen is a reactive flexing or rebounding of the stop lever mechanism that allows the stop block face to be overcome and the drawer and the inner channel member then pulled completely and unexpectedly out the drawer slide assembly. This unexpected event can cause damage or injury since the user is not normally aware that it is going to happen.